In computer vision, mathematical techniques are used to detect the presence of and recognize various elements of the visual scenes that are depicted in digital images. Localized portions of an image, known as features, may be used to analyze and classify an image. Low-level features, such as interest points and edges, may be computed from an image and used to detect, for example, people, objects, and landmarks that are depicted in the image. Machine learning algorithms are often used for image recognition.
The ACT-VISION system (Active Coordinated Tracking for Multi-Camera Systems), available from SRI International, is an object tracking system that uses computer vision techniques to detect and track objects depicted in video images, in a multi-camera system. Aspects of the ACT-VISION system are described in U.S. Pat. No. 8,180,107, which is incorporated herein by this reference in its entirety.
Some technologies of SRI International relating to camera calibration, alignment and geo-localization of images are described in, for example, U.S. Patent Application Publication No. 2012/0314935 and U.S. Pat. Nos. 7,359,626 and 7,613,323, each of which is incorporated herein by this reference in its entirety. Other technologies of SRI International relating to pedestrian tracking are described in, for example, U.S. Pat. Nos. 7,929,017; 7,929,728; and 8,289,390.